Knitted openwork elastic mesh fabric

ABSTRACT

Warpwise and weftwise stretchable seamless tubular knitted openwork mesh fabric comprising a series of individual lengthwise extending warp strings arranged in circumferentially spaced parallel aray interknitted at equally spaced points along the lengths thereof with the spaced convolutions of a weftwise extending helically arranged strand of elastic yarn, each of the strings consisting solely of successive groups of a like number of crochet knitted chain stitches formed solely of non-elastic yarn and of single stitches formed solely of elastic yarn, the elastic yarn stitches being disposed between and being interknit with the proximate chain stitches of the successive groups thereof whereby each warp string is formed of warpwise spaced single elastic stitches arranged in alternating relation with respect to the successive groups of chain stitches, the nonelastic yarn extending warpwise in non-knitted condition as a float of yarn between the proximate chain stitches of the successive groups thereof, the elastic yarn stitches being in unknit linear formation when the fabric is in relaxed condition and being formable into knit confromation by the force exerted upon the warp strings when the fabric is in warpwise stretched condition, in which latter condition the interaction between the proximate chain stitches of non-elastic yarn stitches is such as to inhibit weftwise displacement of the warp strings.

United States Patent 1 1 Levin 51 Feb. 18, 1975 1 KNITTED OPENWORK ELASTIC MESH FABRIC [76] Inventor: Nathan Levin, 416 Highgate Dr.,

Trenton, NJ. 08618 [22] Filed: Apr. 5, 1974 [21] Appl. No.: 458,201

Related U.S. Application Data [63] Continuation of Ser. No. 279,520, Aug. 10, 1973,

abandoned.

[52] U.S. C1. 66/195 [51] Int. Cl D04b 21/100 [58} Field of Search 66/192, 193, 9 R, 9 A, 66/10, 195,172 E, 135

[56] References Cited UNITED STATES PATENTS 2,103,625 12/1957 Longtin 66/172 E 2,120,939 6/1938 Longtin 66/9 R 2,306,246 12/1942 Davis 66/172 E 3,178,910 4/1965 Hammerle 66/193 UX 3,248,905 5/1966 Krauss et al. 66/192 3,513,668 5/1970 Mintz 66/195 3,592,024 7/1971 Levin 66/9 R FOREIGN PATENTS OR APPLICATIONS 1,207,030 9/1970 Great Britain 66/193 Primary E.raminerW. C. Reynolds Assistant Examiner-Andrew M. Falik [57] ABSTRACT Warpwise and weftwise stretchable seamless tubular knitted openwork mesh fabric comprising a series of individual lengthwise extending warp strings arranged in circumferentially spaced parallel aray interknitted at equally spaced points along the lengths thereof with the spaced convolutions of a weftwise extending helically arranged strand of elastic yarn, each of the strings consisting solely of successive groups of a like number of crochet knitted chain stitches formed solely of non-elastic yarn and of single stitches formed solely of elastic yarn, the elastic yarn stitches being disposed between and being interknit with the proximate chain stitches of the successive groups thereof whereby each warp string is formed of warpwise spaced single elastic stitches arranged in alternating relation with respect to the successive groups of chain stitches, the non-elastic yarn extending warpwise in non-knitted condition as a float of yarn between the proximate chain stitches of the successive groups thereof, the elastic yarn stitches being in unknit linear formation when the fabric is in relaxed condition and being formable into knit loop confromation by the force exerted upon the warp strings when the fabric is in warpwise stretched condition, in which latter condition the interaction between the proximate chain stitches of non-elastic yarn stitches is such as to inhibit weftwise displacement of the warp strings.

1 Claim, 6 Drawing Figures 1 KNITTED OPENWORK ELASTIC MESH FABRIC This application is a continuation of pending application Ser. No. 279,520, and now abandoned filed Aug. 10. I973.

The present invention relates generally to the art of knitting and more particularly to circularly knit stretchable tubular mesh net fabric of indefinite length, and to the method of making the same on a multi-feed latch needle circular knitting machine, the fabric being designed for general use as netting and as such is particularly useful as a shape-retaining fabric enclosure for various food products including meat, poultry, cheese and the like.

The present invention is an improvement upon the fabric netting and the method of making the same as disclosed in US. Pat. No. 3,592,024 to Nathan Levin.

The fabric shown in the said Levin patent is made of a plurality of lengthwise extending warp strings circumferentially spaced about the fabric with each such string made up of a continuous series of chain stitches of a relatively non-elastic yarn, and of an elastic yarn extending weftwise peripherally about the fabric in spaced convolution spiral form in generally transverse relation to the warp strings, with the elastic yarn incorporated, without being knitted, in spaced chain stitches of the warp strings, the arrangement being such that the warp strings and the elastic yarn provided openwork therebetween with the elastic yarn providing for transverse stretchability of the fabric. Such fabric has minimal lengthwise stretchability since the chain stitches of the warp strings are made of relatively non-elastic yarns. In this fabric the warp strings are readily slidable along the elastic weft yarn, particularly so when the weft yarn is in stretched condition as it is during transverse stretching of the fabric.

The fabric shown in the said Levin patent is made upon a series of latch needles in a multi-feed circular knitting machine by forming a continuous series of chain stitches of relatively non-elastic yarn upon each of the needles at each of the feeds of the machine and by feeding elastic yarn under suitable tension at one feed of the machine in such manner as to be incorporated, without being knit, in spaced chain stitches of each of the warp strings.

It is a principal object of the present invention to provide an improvement in the stitch structure of the fabric shown in said Levin patent whereby the fabric has limited lengthwise stretchability, in addition to its transverse stretchability, and whereby movement of the warp strings along the elastic weft yarn is restricted, particularly so when the fabric is in stretched condition.

In the improved fabric the stitch structure of each warp string comprises spaced groups of crochet knitted chain stitches of non-elastic yarn separated by spaced unknitted stitches of weft knitted elastic yarn, each unknitted stitch being drawn through the last formed chain stitch of each group thereof and the first formed chain stitch of the next succeeding group thereof being drawn through said each unknitted stitch.

The term unknitted stitch" or unknit stitch as applied to the weft knitted stitches of elastic yarn of the present invention is intended to indicate that the stitch of elastic yarn which, as initially made by the needle drawing the same in tension elongated condition through a preceeding stitch is of U-shaped loop formation, upon subsequently leaving the needle making the same and while in relaxed condition in the fabric becomes degenerated or straightened out from its loop shape to assume a substantially rectilinear condition due to the inherent characteristic of the elastic yarn itself. When a fabric containing such unknit stitches of elastic yarn is subjected to walewise extending stretch or tension, the unknit elastic yarn stitches are caused to temporarily reknit, i.e., to be partially reformed into loop shape while under the effect of such stretch or tension with the size or extent of such re-formed loop shape being proportional, within limits, to the amount of the walewise stretch or tension to which the fabric is subjected.

As the elastic yarn resumes its above mentioned rectilinear shape in the unknitted stitches thereof, it causes deformation of the adjoining chain stitches knit therewith, in consequence of which such deformed chain stitches closely embrace the unknitted elastic yarn stitch and serve to restrict movement of the warp strings along the weftwise extending elastic yarn. These deformed chain stitches are the aforesaid last and first formed chain stitches of consecutive groups of chain stitches separated from one another by their intervening unknit stitch of elastic yarn.

Other objects and advantages of the invention will be apparent more fully hereinafter, it being understood that the present invention consists substantially in the relative arrangement of the several yarns composing the fabric, and in the method of fabricating the same, all as will be described in detail hereinafter, as shown in the accompanying drawings which are illustrative of a preferred embodiment of the fabric and of a method of making the same, and as set forth in the appended claims.

IN THE DRAWINGS FIG. 1 is a side elevational view of the tubular circular knit openwork mesh fabric of the present invention showing its plurality of lengthwise extending circumferentially spaced warp strings and its elastic yarn in spaced convolution spiral formationtion incorporated with spaced chain stitches of the warp strings;

FIG. 2 is an enlarged stitch diagram of a portion of the fabric of FIG. 1 showing the chain stitches in a portion of two of the warp strings along with a portion of two convolutions of the elastic yarn interknit with spaced ones of the chain stitches, the elastic yarn stitches appearing in unknitted condition;

FIG. 3 is an enlarged stitch diagram of a portion of a warp string showing the elastic yarn stitch arranged in knit loop formation;

FIG. 4 is an enlarged stitch diagram, similar to FIG. 3, showing the elastic yarn stitch in partially reknitted condition;

FIG. 5 is an enlarged showing of the type of covered elastic weft yarn used in the present fabric; and

FIG. 6 is a schematic arrangement showing the method of knitting the present improved fabric on a series of needles at four feeds of a circular knitting machine.

Referring now to the drawings, and more particularly to FIG. 1, it will be observed that fabric 10 of the present invention is in the form of an open work mesh net fabric of tubular shape of indefinite length and which comprises a plurality of lengthwise extending circumferentially spaced generally parallel warp strings ll which are jointed together by a weft yarn 12 extending peripherally about said fabric in spaced convolution spiral formation therein. A portion of the wall of fabric is shown broken away inside the dot dash lines 10a.

As shown in FIG. 2, each warp string 11 is formed of longitudinally spaced separate groups of chain stitches 13a, 13b and 130 of a yarn l4 and of spaced unknitted stitches 12a of weft yarn 12, the unknitted stitches being interposed between the successive groups of the chain stitches. Each chain stitch 13a is drawn through an unknitted stitch 12a and each unknitted stitch 12a is drawn through each chain stitch 130, the yarn l4 floating walewise in non-knitted condition between spaced chain stitches 13c and 13a. It will be noted that upon the removal of elastic yarn 12 from any of the warp strings, the stitches thereof will ravel back from the point of such removal. The yarn 14 of the chain stitches is preferably of relatively non-elastic textile material of any suitable type, such as cotton, while the weft yarn 12 is preferably of suitably stretchable textile material such as elastic yarn. The yarn 12, as shown in FIG. 5, may comprise a core 121; of rubber or other natural or synthetic material which is double covered by plural strands 12c and 12d of cotton or other suitable material, the cotton strands being spirally wound about the core in opposite directions. The yarn 12 is in relaxed condition in FIG. 5 and it will be understood that when it is extended under tension its diameter decreases and its covering strands become somewhat spaced. The chain stitches adjoining unknitted stitches 12a are deformed and embrace the same thereby restricting movement of the warp strings 11 along the elastic weft yarn.

The method of making the fabric of FIG. 1 will be de-' scribed with refeferic e tosaid Levin patent and to FIG. 6. It will be noted that in the patent the needles N are wrapped by and knit the individual warp yarns at each of the four feeds of the machine to form individual warp strings of continuous chain stitches while the elastic yarn is fed under tension at one only of the feeds in such manner as to be incorporated unknit in spaced ones of the chain stitches in each of the warp strings.

In the present method, the needles N are wrapped by and knit the individual warp yarns at each of three only of the four feeds of the machine to form spaced groups of three chain stitches, while, only the elastic yarn, under tension, is fed to the needles at the remaining feed of the machine to form spaced elastic yarn disposed between successive groups of the chain stitches.

As shown in FIG. 6, sixteen latch needlesN are schematically shown (without their latches for the sake of clarity) in conjunction with four knitting feeds or stations indicated at A, B, C and D. At feeds AB and C, the warp yarns are shown as being fed to and knit by all of the needles at these feeds, while at feed D the warp yarns 14 are not fed to the needles N and an elastic yarn 12, under suitable tension, is fed to the hooks of the needles which knit stitches thereof at the feed D. Such elastic yarn stitches knit at feed D are drawn through the chain stitches formed on the needles at feed A. This method of knitging may be carried out on the machine shown in said Levin patent by the removal of cam 21a thereof and by raising the feeding position of the elastic yarn (numbered 17 in the patent) so that it is fed directly into the hooks of the needles, the tension upon the elastic yarn being retained.

Each of the elastic yarn stitches made at feed D is shown at 12a in its knit loop formation, FIG. 3, as it is drawn by one of the needles. The elastic yarn of this stitch 120, FIG. 3, being under tension is of reduced diameter and, after elastic stitch 12a leaves the needle forming the same, the elastic yarn of this stitch, as it resumes its relaxed or non-tensioned condition, becomes unknitted and returns to its full diameter and to its linear configuration as seen in FIG. 2. The elastic yarn stitches are properly referred to as unknitted stitches since the adjacent chain stitches 13a and 13c remain interknitted therewith. The fabric being made is subjected to take-up tension and contracts as it comes off the circle of needles making the same.

A partially reknitted stitch 12a is shown in FIG. 4 in the position it will assume when the fabric is stretched lengthwise. It will be understood that the fabric has limited lengthwise stretchability because the fully unknitted elastic stitches will become partially reknitted upon the application of force lengthwise of the fabric. During lengthwise stretching of the fabric a certain amount of force is exerted by chain stitches 13a and 13c on the elastic yarn of the partially reknitted stitches 12a, or conversely, an equal and opposite force is exerted by the partially reknitted stitches 12a on the chain stitches 13a and 13c. This force is the result of the resistance to change in shape of the elastic yarn from fully unknitted to partially reknitted state. In addition to wailwise deformation of the elastic yarn said lengthwise stretching also causes the chain stitches 13a and 13c to tightly embrace the elastic yarn and to dig into its cotton coverings 12c and 12d. The extent to which the unknitted stitches become only partially reknitted will depend upon the amount of force exerted in lengthwise direction upon the fabric.

In the normal use of the present fabric it is stretched or expanded over the particular product upon which it is to be used and it remains in such expanded condition during such use. In such expanded condition, and while the fabric is being placed over the product, it is subjected to lengthwise and to transverse stretching thereof. The lengthwise stretching causes the elastic yarn stitches to assume their partially reknitted configuration of FIG. 4 wherein the adjoining chain stitches 13a and tightly embrace the elastic yarn and its cotton coverings with the result that, for all practical purposes, movement of the warp strings along the elastic yarn is effectively prevented during the placement of the fabric over the product, as well as thereafter.

While the presently disclosed fabric shows the chain stitches of non-elastic yarn in each group thereof to be three in number, it will be understood that the number of chain stitches in each such group may vary and may be more or less than three, and that the unknit elastic yarn stitches between successive groups of chain stitches in each warp string will be spaced accordingly. The number of feeds required on a circular knitting machine to make the fabric, containing a single end of elastic yarn arranged in single course spiral formation, is equal to the number of chain stitches in each group thereof, plus one. Obviously the fabric may contain more than a single end of elastic yarn, and for fabric containing two ends of elastic yarn arranged in two course spiral formation wherein the convolutions are equally spaced and wherein the number of chain stitches in each group thereof are unchanged, the number of feeds required on a circular knitting machine is equal to twice the number required for fabric containing a single end of elastic yarn.

Although the present stitch construction has been shown as incorporated in seamless tubular fabric and has been described as being made upon a multi-feed circular knitting machine, it will be apparent that the improved stitch construction is not so limited and may also be incorporated in other fabrics either tubular or flat, as made upon other types of knitting machines. Further, while the elastic yarn stitches in relaxed fabric are shown in fully unknitted condition, FIG. 2, it is within the scope of the invention to have the elastic yarn stitches in partially reknitted condition in relaxed fabric.

In US. Pat. No. 3,513,668 to Mintz, FIGS. 1-3 show the same fabric construction as disclosed in the above Levin patent, and, in FIG. 4, Mintz shows a modified form of construction in which the elastic yarn and the non-elastic yarns are knitted together, both yarns being shown in knit loop configuration. The present fabric construction differs from that of FIG. 4 of Mintz in that only the elastic yarn is knitted while the non-elastic yarn is present as a non-knitted float extending past the elastic yarn stitch which is in unknit condition when the fabric is in relaxed condition. The result of forming only the elastic yarn into an unknitted stitch results in (a) a substantial saving of the non-elastic yarn, (b) creates a less bulky stitch structure, and (c) allows the proximate chain stitches on both sides of the unknit elastic yarn stitch to urge the same into knit loop configuration when the fabric is subjected to walewise stretching thereby inhibiting weftwise movement of the warp chains.

What is claimed as new and useful is:

I. Seamless tubular knitted openwork mesh fabric of indefinite length comprising a circular series of individual lengthwise extending warp strings arranged in circumferentially spaced parallel array interknitted at equally spaced points along the lengths thereof with spaced convolutions of a single weftwise extending helically arranged strand of elastic yarn, such arrangement providing the fabric with quadrangular-shaped mesh openings, each of said warp strings consisting solely of successive groups of a like plurality of crochet knitted chain stitches formed of non-elastic yarn and of single stitches formed solely of said elastic yarn disposed between and interknit with said successive groups of chain stitches whereby each said warp string is formed solely of longitudinally spaced single stitches of said elastic yarn arranged in alternating relation with respect to said successive groups of chain stitches, each stitch of the elastic yarn having been drawn through the last-formed stitch of a group of said chain stitches and the first-formed stitch of each group of said chain stitches having been drawn through a stitch of the elastic yarn, said stitches of elastic yarn being in unknit formation wherein the yarn thereof extends in linear condition in said helical arrangement of said elastic yarn when said fabric is in relaxed condition, such linear condition of said unknit stitches being due solely to the inherent characteristic of said elastic yarn itself, said nonelastic yarn floating lengthwise in non-knitted condition across said unknit elastic yarn stitches and between said last and said first formed stitches of immediately adjoining groups of said non-elastic yarn chain stitches, said elastic yarn comprising a lengthwise extending elastic core covered with transversely extending windings of yarn, only said last and said first-formed chain stitches of immediately successive groups thereof commonly embracing the unknit stitches of elastic yarn disposed therebetween in such manner that force exerted in lengthwise direction upon said fabric is exerted directly upon said groups of warp chains and causes only said last and said first-formed chain stitches of said groups thereof to correspondingly exert force in opposite directions upon said unknit stitches of elastic yarn therebetween thereby to urge the return of the same to knit loop conformation whereby said non-elastic yarn of said last and of said first-formed chain stitches of immediately successive groups thereof are caused to interengage with said windings of the elastic yarn in said unknit stitches thereof thereby to inhibit displacement of said warp strings transversely of said fabric and to maintain intact the integrity of said mesh openings therein the said fabric being formed solely of said elastic and of said non-elastic yarns arranged in the manner 

1. Seamless tubular knitted openwork mesh fabric of indefinite length comprising a circular series of individual lengthwise extending warp strings arranged in circumferentially spaced parallel array interknitted at equally spaced points along the lengths thereof with spaced convolutions of a single weftwise extending helically arranged strand of elastic yarn, such arrangement providing the fabric with quadrangular-shaped mesh openings, each of said warp strings consisting solely of successive groups of a like plurality of crochet knitted chain stitches formed of non-elastic yarn and of single stitches formed solely of said elastic yarn disposed between and interknit with said successive groups of chain stitches whereby each said warp string is formed solely of longitudinally spaced single stitches of said elastic yarn arranged in alternating relation with respect to said successive groups of chain stitches, each stitch of the elastic yarn having been drawn through the last-formed stitch of a group of said chain stitches and the first-formed stitch of each group of said chain stitches having been drawn through a stitch of the elastic yarn, said stitches of elastic yarn being in unknit formation wherein the yarn thereof extends in linear condition in said helical arrangement of said elastic yarn when said fabric is in relaxed condition, such linear condition of said unknit stitches being due solely to the inherent characteristic of said elastic yarn itself, said nonelastic yarn floating lengthwise in non-knitted condition across said unknit elastic yarn stitches and between said last and said first formed stitches of immediately adjoining groups of said non-elastic yarn chain stitches, said elastic yarn comprising a lengthwise extending elastic core covered with transversely extending windings of yarn, only said last and said first-formed chain stitches of immediately successive groups thereof commonly embracing the unknit stitches of elastic yarn disposed therebetween in such manner that force exerted in lengthwise direction upon said fabric is exerted diRectly upon said groups of warp chains and causes only said last and said first-formed chain stitches of said groups thereof to correspondingly exert force in opposite directions upon said unknit stitches of elastic yarn therebetween thereby to urge the return of the same to knit loop conformation whereby said nonelastic yarn of said last and of said first-formed chain stitches of immediately successive groups thereof are caused to interengage with said windings of the elastic yarn in said unknit stitches thereof thereby to inhibit displacement of said warp strings transversely of said fabric and to maintain intact the integrity of said mesh openings therein the said fabric being formed solely of said elastic and of said non-elastic yarns arranged in the manner set forth. 